Sandy beaches have received increasing attention due to their global ubiquity and ecological services they provide. Previous investigations on their microbial diversity mostly targeted low energy beaches, lacked seasonality or geochemical information. We now have used a multidisciplinary approach to study the microbial diversity within sediments of a sandy, high energy beach that additionally exhibits submarine groundwater discharge (SGD) in the intertidal. We sampled two transects at three seasons down to a depth of one meter for 16S rRNA gene amplicon sequencing and subsequent correlation of microbial diversity to physico-chemical parameters. We found that advection driven transport of porewater constituents and constant physical reworking of the sediments prevented a distinct formation of vertically stratified redox zones. Consequently, a uniform microbial core community of generalists established independently of sampling site and depth. During spring, the community structure was disturbed by a “subsurface bloom” of Bacteroidetes and Firmicutes, probably due to deeper oxygen and nitrate penetration depths. In summer, the community returned to its equilibrium state with imprints of the subsurface bloom still visible. In our study, we did not detect a clear impact of SGD on microbial diversity, but found an unexpected homogeneous composition and resilience of the microbial community structure.

中文翻译：

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桑迪高能海滩微生物多样性的季节性动态揭示了一个有弹性的核心社区

沙滩因其遍布全球的生态服务而受到越来越多的关注。先前对其微生物多样性的调查主要针对低能量海滩，缺乏季节性或地球化学信息。我们现在已经使用多学科方法来研究沙质、高能海滩沉积物中的微生物多样性，该海滩在潮间带中还表现出海底地下水排放 (SGD)。我们在三个季节对两个断面进行了采样，深度一米，用于 16S rRNA 基因扩增子测序以及随后微生物多样性与物理化学参数的相关性。我们发现孔隙水成分的平流驱动运输和沉积物的不断物理再加工阻止了垂直分层氧化还原带的明显形成。最后，一个统一的微生物核心群落，独立于采样地点和深度而建立。在春季，群落结构受到拟杆菌和厚壁菌的“地下大量繁殖”的干扰，这可能是由于氧气和硝酸盐渗透深度较深。在夏季，该群落恢复到其平衡状态，地下绽放的痕迹仍然可见。在我们的研究中，我们没有检测到 SGD 对微生物多样性的明显影响，但发现了微生物群落结构出乎意料的同质组成和弹性。社区恢复到平衡状态，地下绽放的痕迹仍然可见。在我们的研究中，我们没有检测到 SGD 对微生物多样性的明显影响，但发现了微生物群落结构出乎意料的同质组成和弹性。社区恢复到平衡状态，地下绽放的痕迹仍然可见。在我们的研究中，我们没有检测到 SGD 对微生物多样性的明显影响，但发现了微生物群落结构出乎意料的同质组成和弹性。